Impacts of long-term climate change on the soils and hydrology of the Atacama Desert, northern Chile

Program or topic of research:

Impacts of long-term climate change on the soils and hydrology of the Atacama Desert, northern Chile

Department or unit:

Department of Earth & Atmospheric Sciences
College of Engineering Energy Institute

Contact Information

Teresa Jordan
Professor and Faculty Fellow, Atkinson Center for a Sustainable Future
teresa.jordan@cornell.edu

Program goals

Much of the foundation of Chile’s economy rests on three natural resources in the Atacama Desert that themselves depend on climate: the very scarce fresh groundwater, the very unusual saline soils, and saline groundwater (brines) in salt deposits. The water resources of the Atacama are fundamental to copper mining, some of the saline soils are nitrate and iodine ore, and the brines are a major source of lithium. Our goal is to relate the amount and physical distribution of groundwater to the history of past climate change, in part utilizing knowledge extracted from the geological history of the gypsum-rich soil. Our goal is also to assist water managers to incorporate that emerging knowledge of groundwater recharge in their management of the water resources.

Brief description

The water system of the Loa River basin in northern Chile’s Atacama desert includes a broad swath from the Andean highlands to the Pacific ocean, although subsurface fresh groundwater aquifers and surface water streams are largely focused along a thin corridor defined by the Loa River and its two major tributaries. In recent decades the human use of the water resources advanced from reliance on the surface water, to also include important extraction from aquifers. Yet there is little documentation of the physical distribution of the groundwater, of the interconnections between what are perceived as separate aquifers, and of the amount of time needed for water to recharge those aquifers. There is also little appreciation for the complexities of the long-term interconnections between economic outcomes and water management choices.

With paleo-ecologists and geochemists, we completed studies of the variations through the last 300,000 years in precipitation in the Atacama Desert and adjacent, somewhat wetter, Andes. In progress are studies of million-year-scale climate variations, which leave records of changes of soil production and of erosion across the plains between the rivers that are linked to fluctuations in the amount of precipitation.

Our research, in collaboration with water chemists, hydrologists and economists from other universities, also probes groundwater problems. To map the extent and properties of the aquifers, we are using subsurface data obtained by companies for purposes unrelated to groundwater. We are using the chemistry of minerals deposited from springs and of the water from wells and rivers to evaluate the paths along which groundwater flows. To compare the length of time the water has been in an aquifer to the history of past climate states, we are using the isotopic composition of well water and spring water. With economists, we are exploring the dynamic connections between decisions regarding aquifer pumping, costs and benefits.

Website

http://www.geo.cornell.edu/geology/faculty/TEJ/index.html

Key publications

Nester, P. L., Gayó, E., Latorre, C., Jordan, T. E., and Blanco, N., 2007, Perennial stream discharge in the hyperarid Atacama Desert of northern Chile during the latest Pleistocene: Proceedings of the National Academy of Sciences, v. 104, no. 50, p. 19724-19729, doi: 10.1073/pnas.0705373104

Gayó, E. M., Latorre, C., Jordan, T. E., Nester, P. L., Estay, S. A., Ojeda, K. F., and Santoro, C. M., 2012, Late Quaternary hydrological and ecological changes in the hyperarid core of the northern Atacama Desert (~21°S): Earth-Science Reviews, v. 113, p. 120-140, doi: 10.1016/j.earscirev.2012.04.003

Godfrey, L. V., Jordan, T. E., Lowenstein, T. K., and Alonso, R. L., 2003, Stable isotope constraints on the transport of water to the Andes   between 22 degrees and 26 degrees S during the last glacial cycle: Palaeogeography Palaeoclimatology Palaeoecology, v. 194, no. 1-3, p. 299-317, doi: 10.1016/S0031-0182(03)00283-9

Bobst, A. L., Lowenstein, T. K., Jordan, T. E., Godfrey, L. V., Ku, T. L., and Luo, S. D., 2001, A 106 ka paleoclimate record from drill core of the Salar de Atacama,   northern Chile: Palaeogeography Palaeoclimatology Palaeoecology, v. 173, no. 1-2, p. 21-42



Category: Earth & Atmospheric Sciences, Ecosystems, Research, Terrestrial, Water/flooding

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